Keeping the streets clear is a lot of work.
Not only did the engine have trouble starting this morning but it wouldn't idle, either, but kept turning off. I drove the car to the parking lot of a auto repair shop I use and turned off the engine. After a bit, it started normally and managed to idle. Then I drove the extra 20 km, after which the engine worked normally. However, the traction control system light was still on when I parked the car inside our garage.
When I took the car out of the garage a couple of hours later, everything was perfectly normal again. Everything was working perfectly normally when I last drove the car a couple of hours ago.
I suspect the problem was that snow that had potentially melted and then frozen again in the garage had caused some sensor or a few to malfunction. It's also possible that the battery will have to be replaced at some point. I'm going to ask the mechanic to run a diagnostic on the battery next time when I take the car to the annual maintenance. It's possible that the very cold weather last night and stopping a few times to take photos as well as the start/stop mechanism strained the battery that already had a relatively low charge to an extent that exposed the fact that it is nearing the end of its life. A battery test with the correct device should expose a bad battery. This car is only five and a half years old but not every battery is as good as the one in our other car that lasted for ten years. That one caused electrical problems for a year before I realized that it must have been the battery.